# Source code for nacl.pwhash

    # Copyright 2017 Donald Stufft and individual contributors
    #
    # Licensed under the Apache License, Version 2.0 (the "License");
    # you may not use this file except in compliance with the License.
    # You may obtain a copy of the License at
    #
    # http://www.apache.org/licenses/LICENSE-2.0
    #
    # Unless required by applicable law or agreed to in writing, software
    # distributed under the License is distributed on an "AS IS" BASIS,
    # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    # See the License for the specific language governing permissions and
    # limitations under the License.

    from nacl.exceptions import CryptPrefixError

    from . import _argon2, argon2i, argon2id, scrypt

    STRPREFIX = argon2id.STRPREFIX

    PWHASH_SIZE = argon2id.PWHASH_SIZE

    assert _argon2.ALG_ARGON2_DEFAULT == _argon2.ALG_ARGON2ID13
    # since version 1.0.15 of libsodium

    PASSWD_MIN = argon2id.PASSWD_MIN
    PASSWD_MAX = argon2id.PASSWD_MAX
    MEMLIMIT_MAX = argon2id.MEMLIMIT_MAX
    MEMLIMIT_MIN = argon2id.MEMLIMIT_MIN
    OPSLIMIT_MAX = argon2id.OPSLIMIT_MAX
    OPSLIMIT_MIN = argon2id.OPSLIMIT_MIN
    OPSLIMIT_INTERACTIVE = argon2id.OPSLIMIT_INTERACTIVE
    MEMLIMIT_INTERACTIVE = argon2id.MEMLIMIT_INTERACTIVE
    OPSLIMIT_MODERATE = argon2id.OPSLIMIT_MODERATE
    MEMLIMIT_MODERATE = argon2id.MEMLIMIT_MODERATE
    OPSLIMIT_SENSITIVE = argon2id.OPSLIMIT_SENSITIVE
    MEMLIMIT_SENSITIVE = argon2id.MEMLIMIT_SENSITIVE

    str = argon2id.str

    assert argon2i.ALG != argon2id.ALG

    SCRYPT_SALTBYTES = scrypt.SALTBYTES
    SCRYPT_PWHASH_SIZE = scrypt.PWHASH_SIZE
    SCRYPT_OPSLIMIT_INTERACTIVE = scrypt.OPSLIMIT_INTERACTIVE
    SCRYPT_MEMLIMIT_INTERACTIVE = scrypt.MEMLIMIT_INTERACTIVE
    SCRYPT_OPSLIMIT_SENSITIVE = scrypt.OPSLIMIT_SENSITIVE
    SCRYPT_MEMLIMIT_SENSITIVE = scrypt.MEMLIMIT_SENSITIVE

    kdf_scryptsalsa208sha256 = scrypt.kdf
    scryptsalsa208sha256_str = scrypt.str
    verify_scryptsalsa208sha256 = scrypt.verify

    def verify(password_hash: bytes, password: bytes) -> bool:
        """
        Takes a modular crypt encoded stored password hash derived using one
        of the algorithms supported by `libsodium` and checks if the user provided
        password will hash to the same string when using the parameters saved
        in the stored hash
        """
        if password_hash.startswith(argon2id.STRPREFIX):
            return argon2id.verify(password_hash, password)
        elif password_hash.startswith(argon2i.STRPREFIX):
            return argon2id.verify(password_hash, password)
        elif scrypt.AVAILABLE and password_hash.startswith(scrypt.STRPREFIX):
            return scrypt.verify(password_hash, password)
        else:
            raise (
                CryptPrefixError(
                    "given password_hash is not in a supported format"
                )
            )